Background and purpose: The Pediatric Stroke Outcome Measure (PSOM) is an objective, disease-specific outcome measure containing 115 test items suitable for newborn to adult ages. The PSOM measures neurological deficit and function across 5 subscales: right sensorimotor, left sensorimotor, language production, language comprehension, and cognitive/behavior yielding a final 10-point deficit score. The goal of this study was to examine PSOM construct validity in measuring neurological outcome in pediatric stroke survivors and interrater reliability (IRR) for both prospective and retrospective scoring.
Methods: For construct validity, PSOM subscale scores were correlated with scores on standardized neuropsychological measures matched by functional domain. We assessed IRR by comparing same-day "live" PSOM scores from 2 independent raters in 10 children (prospective IRR) and by comparing PSOM scores estimated from medical dictations across 5 raters in another 10 children (retrospective IRR).
Results: We analyzed PSOM scores from 203 children with ischemic stroke. PSOM subscales show good construct validity (ρ=0.2-0.4; P<0.05). PSOM subscale scores of normal/abnormal demonstrate strong agreement for domain-matched neuropsychology scores (alternative chance-corrected statistic=0.4-0.8). IRR was excellent with the 2 prospective raters' scores in almost perfect agreement (intraclass correlation coefficient, 0.93; 95% CI, 0.76-0.98). Retrospective IRR demonstrated strong agreement with an intraclass correlation coefficient of 0.77 (95% CI, 0.56-0.92).
Conclusions: The PSOM is a valid and reliable outcome measure for pediatric stroke. It is useful for retrospective scoring from health records and prospective serial longitudinal outcome assessments and is ideally suited for prospective clinical trials in pediatric stroke.